Lapping machine



March 3, 1942. H. s. INDGE LAPPING MACHINE 3 Sheets-Sheet 2 Filed Feb.8, 1939 March 3, 1942.

H. s. INDGE V 2,275,061

LAPPING MACHINE Filed Feb. 8, 1939 :s Shee ts-Sheet s HEBEERTSJNDGEPatented Mar. 35 1942 LAPPIN G MACHINE Herbert S. Indge, Westboro, Mass"alslgnor to Norton Company, Worcester, Mass., a corporation ofMassachusetts Application February 8, 1939, Serial No. 255,298

' 3 Claims. (Cl. 51-117) The invention relates to lapping machines, andmore particularly to a micro-lapping machine for producing an accuratesurface of high quality on either a cylindrical or flat work piece.

One object of the invention is to provide a simple and thoroughlypractical lapping machine for producing fine finishes on work pieces.Another obiect of the invention is to provide an im proved lappingmachine in which either flat or cylindrical work pieces are lappedbetween a pair of opposed relatively rotatable lapping elements. Afurther object of the invention is to provide an improvedlapping machinehaving a pair of op posed relatively rotatable lapping elements whichare relatively revolved to produce a combined rotary and planetarymovement of the lapping v element relative to the work piece. Otherobjects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction,combinations of elements, and arrangements of parts, as will beexemplified in the structure to be hereinafter described, and the scopeof the application of which will be indicated in the following claims.

In the accompanying drawings, in which is shown one of various possibleembodiments of the mechanical features of this invention:

Fig. l is a vertical sectional view-through a niiicro-lapping machineembodying this inven' Fig.2 is a fragmentary plan view of the machineshown in Fig. 1, showing the driving mechanism for the upperlappingelement;

Fig. 3 is a fragmentary sectional view taken approximately on the line3-3 of Fig. 1, showing the arrangement of the work supporting Fig. 4 isa plan view of the Fig. 3;

Fig. 5 is a modified type of work cage for use in the lapping of flatwork pieces;

Fig. 6 is a modified type of cage adapted for supporting cylindricalwork;

Fig. 7 is a cross sectional view, showing the support for the cageconstruction shown in Figs. 5 and 6; and

Fig. 8 is a fragmentary sectional view of a modified drive for the upperlapping wheel.

The improved lapping machine as disclosed in the drawings comprises abase l0 which supports a pair of opposed spaced lapping elements ordisks II and I2 which are provided with plane lapping surfaces arrangedto engage opposite sides of a work piece to lap the same. The lapworkcage shown in ping element l I is mounted at the lower end'oi' avertically arranged rotatable spindle II which is rotatably joumalledeccentrically within a rotatable'sleeve ii. The spindle l3 and sleeveare each provided with independent driving mechanisms so that thelapping element or wheel H may be rotated about the axis of the wheelspindle l3 and the sleeve Il may be rotated about its axis of rotationto produce a planetary movement of the wheel spindle I 3 and the lappingwheel or element ll.

Similarly, the lower lapping element or wheel i2 is supported on theupper end of a rotatable spindle I5 which is rotatably and eccentricallyjoumalled within a rotatable sleeve or quill IS. The spindle l5 andsleeve or quill l6 are each arranged to be independently rotated so asto rotate the lapping element l2 about the axis of its supportingspindle and to move the lapping element in a planetary motion byrotating the sleeve or quill IS.

A driving mechanism is provided for,rotating and revolving the lappingelements. Ayariable speed electric motor 20 is mounted. within the baseiii of the machine. Apulley 2| mounted on the end of the motor driveshaft is connected by means of a belt 22 with a pulley 23 which ismounted on the outer end of a rotatableshaft 24.

The shaft 24 is journalled in a bearing 25 in the base ill of themachine. A bevel gear 28 is mounted on the inner end of the shaft 24'and meshes with a bevel gear 21 which is in turn keyed to a verticallyarranged rotatable shaft 28. The shaft 28 is journalled within bearings29 and 30 in the base It).

The lower end of the shaft 28 is provided with a pulley 35 which isconnected by means of a belt 38 with alarger diametervpulley 31 which isremovably mounted on the lower end of the lap spindle I! so as to rotatethe lapping wheel i2. An idler pulley 38 is rotatably mounted on. a stud38 which is in turn supported by an idler bracket to take up the slackand to properly tension the driving belt 36. The pulleys 35 and 31 maybe readily changed to facilitate rotating the lapping element l2 at adesired speed.

The upper lapping element II is similarly rotated either in the samedirection or in the opposite direction from the lower lapping elementl2. As illustrated in Fig. 1, a driving mechanism has been shown forrotating the lap spindle It and the lap H in the opposite direction fromthe lap i2. A gear 45 is keyed on the shaft 28.

The gear 45 meshes with a gear 46 which is keyed to a rotatable shaft 41which is joumalled in a 2 bearing 48 in the base I0. A pulley 49 isremovably keyed onto the upper end of the shaft 41 and is connected bymeans of a driving belt 50.

50 and to tension the same so as to transmit the desired rotary motion'to the upper lap l I.

If it is desired to rotate the spindle I3 and lap II in the samedirection as the spindle I5 and lap l2, a pulley 49a (shown in Fig. 8)may be placed in position on the upper end of the shaft 28 between theidler-brackets 54 and 55 and a belt connected between the pulley 49a andthe spindle pulley 5i.

In order to secure the desired and predetermined lapping action, it isdesirable to impart a secondary motion to the lapping elements II andIi. in addition to their rotary motion. In the preferred construction,this movement is a planetary movement whereby the spindle I3 is revolvedas it is rotated about the axis of the sleeve or quill l4, and similarlythe spindle I5 is revolved as it rotates about the axis of the sleeve orquill IS. The vertical drive shaft 28' is provided with a driving gear80 which is slidably keyed thereto and is held in adjusted positlon bymeans of a set screw BI. The gear 60 meshes with a gear 82 which isrotatablysupported on a shaft 63. The shaft 63 is iournalled in bearings84 and 85 in a projecting portion of the base Ill. The gear 62 mesheswith a gear 65 which, as illustrated, is formed by cutting gear teeth inthe peripheral surface of the sleeve or quill l4. The gear 65 is a widefaced gear having relatively wide gear teeth to facilitate longitudinalor axial movement of the quill I4. When the shaft 28 is rotated, itserves not only to transmit rotary motion through the belt 58 and pulley5| to rotate the spindle l3 but also, through the gears 60, 62 and 65,to rotate the may be accomplished by loosening the set screw 1 Si andsliding the gear out of mesh with the gear 66 and then rotating thequill I4 so that the axis of the spindle I3 is on the diametricallyopposite side of the axis of the sleeve or quill I4. The gear 6|! maythen be moved upwardly. 4

To facilitate loading of work pieces into the machine and also toproduce the desired lapping engagement between the laps II and I2relative to the work, it is desirable to provide means for producing arelative approaching and receding movement between the lapping elementsI! and i2. In the construction as illustrated in the drawings, thelapping element II is arranged for movement toward and from the lappingelement I2. The sleeve or quill I4 is slidably mounted within thecylindrical aperture 11 of the base III. Manually operable means isprovided for producing a relative approaching and receding movement.This niay comprise a man-' ually operable spoked wheel 80 which ismounted on the outer end of a shaft 8| which is journalled in the baseIII. The shaft 8| carries a gear 82 which meshes with circular rackteeth 83 formed in the periphery of the sle ve I4. By rotation of thewheel 80 in a clock e direction (Fig. 1), the gear 82 acting upon thecircular rack 83 will cause the quill l4 to move upwardly, thusseparating the upper lap element II. Similarly, the rotation of thewheel 80 in a counterclockwise direction serves to lower the quill l4and the upper lap element II so that it approaches the lower lap I2 andmay be moved into en sleeve or quill I4 to impart a planetary movementto the lapping element II during rotation thereof.

Similarly, a gear 10 is mounted on the drive shaft 28. The gear 10meshes with a gear 12 which is supported on a rotatable shaft I3. Theshaft 13 is joumalled in bearings 14 and I5 in the base Ill. The gear 12meshes with a gear I! formed on the periphery of the sleeve it. It

will be readily apparent from the foregoing disclosure that when theshaft 28 is rotated, a rotary motion is transmitted by the belt 35 andpulley 8-1 to rotate the spindle I5 and the lappin element II about theaxis of the spindle I5, and at the same time the gears 10, I2 and I6serve to rotate the sleeve or quill I8 so as to' impart a planetarymotion to the wheel spindle I5 and lapping element I2 during rotationthereof.

As shown in'Fig. 1 of the drawings, the quills I4 and I8 are timed andpositioned so'that the axes of the spindles I 3'and I5, respectively,are in alignment with each other and travel in alignment duringthe'rotary and planetary movement of the lapping elements II and I2. Ifdesired, 'the quills I4 and It may :be relatively adjusted so that theaxes of the spindles I3 and I5 are out of alignment with each otherduring substantially the entire lapping operation. This gagement with aplurality of work pieces located therebetween. i

To facilitate rotation of the wheel spindle I3 during the verticalmovement of the quill I4, the driving pulleys 49, 48a and the idlerpulley 52 are preferably wide faced pulleys of a width at least equal tothe maximum vertical movement of the quill l4, so that during thisvertical positioning movement of. the upper lap II, the

spindle I3 may be continuously driven by the belt 50.

A suitable work holding cage is provided for locating work piecesbetween the opposed plane faces of the lapping elements II and I2. Asillustrated in Figs. 1, 3 and 4, a work cage is provided having aplurality of non-radially extending work locating spindles 9| whichserve to support a plurality of hollow cylindrical work pieces 92thereon. A fixed guiding plate 94 is provided with a cylindricalaperture 95 slightly larger than the outer periphery of the spoked cage90, 9| with the work pieces mounted thereon so that the cage and workpieces are free to move therewithin. The plate 94 is held in a fixedposition by means of a plurality of spaced studs 96, 91, 98 and 99.These studs are screw threaded into a'pan-s'haped member I00 which isfixed relative to the base I II. A pair of nutsare provided on each ofthe studs 98, 91, 9 8 and 99, one located above and the other below theplate 94. These nuts serve as locating and holding means whereby theplate 94 may be raised or lowered to space it substantially midwaybetween the opposed faces of the lapping wh'eels II and I2. This plate94 is maintained in fixed relationship relative to the machine base andpieces 92 are placed in position within the aperture 85 and the lappingelement II is moved downwardly into engagement with the work pieces 92while the spindles and 'quills are rotated to produce a rotary andplanetary movement of the lapping elements H and I! so as to produce thedesired and predetermined lapping operation on the work pieces 92. Thework pieces, as illustrated in Figs. 1, 3 and 4, are hol-fl lowcylindrical work pieces.

This invention, however, is not limited to cylindrical type work piecesbut is equally applicable to solid work pieces of a cylindrical shape aswell as fiat work pieces in which it is desired to lap opposed flatfaces parallel to each other. Modified cage constructions have beenillustrated in Figs. 5, 6 and '7. In Fig. 5 a cage I05 is provided witha plurality of apertures I06 which are arranged to receive circular workpieces I07 having flat opposed hollow surfaces to be lapped. This cageis applicable to any shape of flat work pieces and apertures areprovided sufliciently large and preferably shaped as clearance holes,

slightly larger than the shape and size of the work pieces to be lapped.

A similar type work cage III) has been illustrated in Fig. 6 for lappingsolid cylindricalwork pieces. Thecage member H9 is provided with aplurality of non-radially arranged slots l I I which are slightly largerthan the work pieces 2 to be lapped. Each of the cages I05 and H isprovided with a peripheral flange Ill (Fig. 7) which is arranged to restupon the upper surface of the fixed plate 94 so as to locate the cage I"or H0 between and I2.

The operation of this machine will be readily apparent from theforegoing disclosure. Assuming the various parts to have been previouslyadjusted and the speed of the motor 20 to have been adjusted by means ofa rheostat (not shown) to produce the desired rotary speed to the driveshaft 28, and also assuming that the proper size of pulleys been mountedin position to produce the desired rotary speed to the lapping elementsII and I2, themachine is then ready for a lapping operation. The lappingelement II is in an upper or raised position and the work cage 90 havinga plurality of work pieces 82 carried thereby is placed in positionwithin the aperture 95 of the fixed guide plate 94. The motor 20 is thenstarted to rotate the spindles II and I! and to rotate the quills l4 andIS so as to impart a rotary and planetary movement to the lappingelements II and I2. The upper lapping element is then. moved downwardlyby rotation of the the lapping elements II' as, 31, 4a and have II andI2 are rotated and planetarily moved. If additional pressure is desiredto increase the cutting action of the lapping wheels ll and II, apressure device (not shown) may be utilized, such as that shown in myprior U. S. Patent No.

r 1,831,958 dated November 17, 1931.

It will thus be seen that there has been pro- 'vided by this inventionapparatus in which the manually operable wheel to move the upper--lapping element ll into. operative engagement with the work pieces 92.The weight of the upper lap may be positioned to produce the desiredlappin action as the lapping elements,

various objectshereinabove set forth together with many thoroughlypractical advantages are successfully achieved. As many possibleembodiments may be made of the above invention and as many changes mightbe made inthe embodiment above set' forth, it is to be understood thatall matter'hereinbefore set forth or shown in the accompanying drawingsis to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a lapping machine having a base, opposed rotatable lappingelernents supported thereby, means relatively to move said elementstoward or from each other, driving means to rotate said elements aboutone axis, driving means simultaneously and positively to revolve saidelements about an axis eccentrically disposed relative to the axis ofrotation during rotation thereof, a freely rotatable work cage betweensaid elements, and means including a fixed guide plate having acylindrical aperture which surrounds said cage to prevent lateralmovement thereof.

2. In a lapping machine having a base, opposed rotatable lappingelements supported thereby, means relatively to movesaid elements towardor from each other, means positively to rotate said elements about oneaxis, driving' means. simultaneously and positively to revolve saidelements about an axis eccentrically disposed relative to the axis ofrotation during rotationthereof, -a freely rotatable work cage betweensaid elements-means including a fixed guide plate having a cylindricalaperture which surrounds saidcage to prevent lateral movement thereof,and means to adjust the position of said plate.

3. In a lapping machine having a base, opposed rotatable lappingelements and a rotatable work cage therebetween, means to move at leastone of said elements relatively toward and from the other, a pair ofrotatable spindles to support said elements, a pair of aligned rotatablesleeves rotatably supported in said base, eccentric bearing supports insaid sleeve for said spindles, a drive shaft, means including a motorpositively to rotate said shaft, driving connections between said shaftand each of said sleeves synchronously to rotate said sleeves, anddriving connections between said shaft and each of said spindlessynchronously to rotate said spindles.

HERBERT S. INDGE.

